1. Field of the Invention
The present invention relates to couplings that fluidly connect flexible tubing; and in particular, the present invention relates to connectors that connect and securely hold tubing of implantable hydraulic devices.
2. Description of the Prior Art
Implantable devices that function or operate under hydraulic principles include flexible tubing sections for transporting fluid from one hydraulic element of the device to another. The tubing sections require connectors to connect and securely hold the tubing for many years after the device has been implanted. Some examples of hydraulic implantable devices include inflatable penile prostheses of the type disclosed in the Strauch et al U.S. Pat. No. 3,853,122, the Uson U.S. Pat. No. 4,009,711, the Finney et al U.S. Pat. No. 4,201,202, the Yamanaka U.S. Pat. No. 4,235,227, the Finney U.S. Pat. No. 4,318,396 and the Buuck U.S. Pat. No. 3,954,102, and urinary incontinence devices such as described in the Buuck U.S. Pat. No. 3,863,622 and the Rosen U.S. Pat. No. 3,903,894.
One specific example, namely the inflatable penile prosthesis, requires that fluid be transferred from a reservoir through tubing to the prosthetic member to inflate the prosthetic member so that an erection occurs. It is desirable that the several elements that comprise the inflatable penile prosthesis, such as the reservoir, pump and inflatable prosthetic members be implanted separately in different locations in the body. Typically, sections of elastic tubing are permanently attached to each of the hydraulic elements. The sections of tubing must then be attached to each other so that the various elements of the prosthesis are fluidly connected with each other.
The tubing is typically made of a medical grade elastomer that is highly elastic and highly compressive. The highly elastic and highly compressive characteristics have caused problems in connecting the tubing and retaining the tubing in a connected state. In many of the devices described above, the connectors used to connect the tubing have not securely held the tubing in place, causing hydraulic fluid to leak from the prosthesis and have required surgery to correct the leak.
One prior art method of connecting the tubing was to connect an end of each tubing section to a rigid stainless steel connector having a constant outer diameter. The tubing was pushed and expanded over the connector body with the fluid passages of the tubing communicating with the fluid passage of the connector. Ends of the tubing sections were slid over the connector and sutured to each other. This type of connection resulted in several problems. First, the tubing varies in wall diameter from batch to batch and the physician had to adjust the suturing techniques to the variations in the tubing wall thickness. Second, suturing of the tubing increased the time of implantation. Third, when the tubing was pressurized, there was a reduction in wall diameter at the suture site and reduced gripping by the tubing of the connector wall due to radial pressure exerted on the elastic tubing by the pressurized fluid. Leakage and an occasional failure resulted in some cases.
Other types of clamping devices that compressively clamp tubing against a rigid connector also have been found to be unsatisfactory for extended periods of time. Since the tubing is highly compressive, along with being high elastic, conventional clamps that hold the tubing by compressive forces, still permit the tubing to "creep" off the connector over an extended period of time.